Intended beneficiary: When may the beneficiary not modify the promise?

• A. If the beneficiary is vested (known and relied upon)
• B. If the contract allows modification
• C. If the promisee revokes the promise
• D. If the promisee and promisor both consent to modification

Answer: (A)

Intended beneficiaries gain enforceable rights once their interests vest. Vesting typically occurs when the contract identifies the beneficiary and the promisee’s obligation to benefit that person is fixed and the beneficiary can rely on it. Once those rights have vested, the beneficiary cannot unilaterally modify the underlying promise; any changes that would affect the beneficiary’s rights must be made with the beneficiary’s consent (or through a modification agreed by the original parties that respects the beneficiary’s interests).

So, the beneficiary cannot modify the promise when they are vested—their rights are fixed and protected, and alterations to the promise cannot be done by the beneficiary alone. The other scenarios describe situations where changes might be possible if the parties agree or the contract allows modification, but they do not erase the protection that vesting provides to the beneficiary.